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Dealer/Warranty Concerns if swapping wheels/tires over to other factory available size?


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Looking to get rid of my 18" Trail Boss Wheels and Tires and put on some 20" AT4 Wheels/Tires.  In looking at doing this swap I found that I would need the HyperTech Speedo Calibrator but also read of some concerns regarding warranty for going to a different size setup than what came on the vehicle.  My truck is brand new, and was curious if anyone had any first hand experience with this type of scenario?

 

Thanks,

 

Rick.

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I doubt GM has changed how they did this on the K2xx trucks, typically the overall tire height for the 18" and the 20" are exactly the same, they use the same Rev's per mile in the ECM. You shouldnt need to change a thing as long as you are using the same tire size as the stock 20" tires.

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The 20" wheel comes stock with a 275/60/20 tire which is a 33" tire, the 18" is smaller 265/65/18 which is a 31.6" tire.  Also, an available tire option is a 275/65/18 which is a 32" tire

Edited by crj19
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17 hours ago, Ricky_Starbucks said:

The AT4 Wheels I am looking to grab are 275/60/R20 which was also an option for the Trail Boss.  Currently my stock wheels are 275/65/R18.

 

Im hoping there would be no negative warranty implications since going to an offered factory option.

 

Thanks,

 

Rick.

 

 

The larger diameter tires would cause an issue for warranty only if they are causing the problem.  So if say your radio quit working, you are fine.  If you have a safety feature not working properly like adaptive cruise or anything that uses the forward facing camera up by the rearview mirror, then yes, the larger tires can be used to deny as those systems are all calibrated to the factory tire size that is programmed to the truck.  

 

That said.  Be careful with ANY speedo calibrator.  Have a read below in the quote box (expand to read the whole thing):

 

Quote

 

#PIT5752B: SPS Programming Issues / No Communication / IPC Gauges Erratic / Various IPC Warning MILs / Certain Cruise Control Speeds Will Not Set / Communication DTCs - (Sep 14, 2021)

 

Subject: SPS Programming Issues / No Communication / IPC Gauges Erratic / Various IPC Warning MILs / Certain Cruise Control Speeds Will Not Set / Communication DTCs

 

Involved Region or Country

North America

Condition

You may encounter any of the following issues:

IPC warning lights or messages

IPC gauges erratic

Cruise control may not set or not set at a certain speed

Issues with SPS programming or reprogramming a module

 

No Communication with various modules

Any of the following DTC's: U0073, U0100, U0101, U0102, U0121, U0128, U0131, U0140, U0415, U0422, U2413, and/or P0700   

 

Cause

The cause of these concerns could be an aftermarket device plugged inline with the BCM X1 connector, shown below.  These aftermarket devices are typically installed to change the speed calibration when a different size wheel/tire is installed.  These devices are not supported or recommended by GM and the conditions created by these aftermarket devices will not be covered under warranty.

 

Correction

Before any in depth repairs are made, inspect the truck for this type of device. This device will be plugged inline with the BCM X1 connector. 

Note: If the vehicle is modified with a lift kit, lowering kit, different size wheels/tires, etc. it is a good indication there could be one of these devices installed.

 

 

 

Plug in devices like the Hypertech end up screwing the communications lines.  Any time a dealer does a reprogram on say ECM, TCM, EBCM or BCM, it will come back with nothing but faults. 

 

GM had a story on this that I would love to find, some guy got hard warranty blocked after a field engineer ended up finding a Hypertech calibrator in the truck.  Customer came in for a transmission concern, they replaced the TCM and during programming it wouldn't take and they lost communications with other modules.  Another TCM, an ECM and EBCM later with still no comms, the field engineer came out and found it.  They unplugged and everything programmed, voided his warranty.  

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29 minutes ago, newdude said:

 

 

The larger diameter tires would cause an issue for warranty only if they are causing the problem.  So if say your radio quit working, you are fine.  If you have a safety feature not working properly like adaptive cruise or anything that uses the forward facing camera up by the rearview mirror, then yes, the larger tires can be used to deny as those systems are all calibrated to the factory tire size that is programmed to the truck.  

 

That said.  Be careful with ANY speedo calibrator.  Have a read below in the quote box (expand to read the whole thing):

 

 

 

Plug in devices like the Hypertech end up screwing the communications lines.  Any time a dealer does a reprogram on say ECM, TCM, EBCM or BCM, it will come back with nothing but faults. 

 

GM had a story on this that I would love to find, some guy got hard warranty blocked after a field engineer ended up finding a Hypertech calibrator in the truck.  Customer came in for a transmission concern, they replaced the TCM and during programming it wouldn't take and they lost communications with other modules.  Another TCM, an ECM and EBCM later with still no comms, the field engineer came out and found it.  They unplugged and everything programmed, voided his warranty.  

Thanks NewDude.  Wonder if a dealer would be willing to recalibrate the BCM for the new factory offered size then?  I'd be willing to pay to have it done right and avoid headaches in the future.

 

I have no adaptive cruise control that I am aware, nor any front facing cameras or sensors due to the supply chain shortages,

 

Thanks again!

 

Rick.

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16 minutes ago, Ricky_Starbucks said:

Thanks NewDude.  Wonder if a dealer would be willing to recalibrate the BCM for the new factory offered size then?  I'd be willing to pay to have it done right and avoid headaches in the future.

 

I have no adaptive cruise control that I am aware, nor any front facing cameras or sensors due to the supply chain shortages,

 

Thanks again!

 

Rick.

 

 

Dealer can do it for factory sizes yes.  Because the Trail Boss has the option for 20's they should be able to.  

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3 hours ago, newdude said:

 

 

Dealer can do it for factory sizes yes.  Because the Trail Boss has the option for 20's they should be able to.  

 

 

No they cant, GM hasnt allowed a reprogram of the BCM since the K2xx (2014+) trucks launched. Doesnt matter if it is a factory size or not, GM TAC has refused those requests for years now hence why people went after the Hypertech programmer to calibrate for tire sizes.

275/60-20 is 32.99" overall height

265/60-20 is 32.52" overall height

275/65-18 is  32.07" overall height

Without looking into the ECM/TCM to see the number GM used, in the past the Rev's per mile that GM used for the speedo were the same for all 3 of the tire sizes GM used on the 1500 series trucks.

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18 minutes ago, TJay74 said:

 

 

No they cant, GM hasnt allowed a reprogram of the BCM since the K2xx (2014+) trucks launched. Doesnt matter if it is a factory size or not, GM TAC has refused those requests for years now hence why people went after the Hypertech programmer to calibrate for tire sizes.

275/60-20 is 32.99" overall height

265/60-20 is 32.52" overall height

275/65-18 is  32.07" overall height

Without looking into the ECM/TCM to see the number GM used, in the past the Rev's per mile that GM used for the speedo were the same for all 3 of the tire sizes GM used on the 1500 series trucks.

 

 

So GM is lying then?  Please explain the document below then.

 

PIT3271K: Guidelines When Changing Tire And Wheel Size - (Nov 11, 2020)

 

Model Year: 2003-2021

 

Supersession Statement

This PI was superseded to update the Model Year. Please discard PIT3271J.

Condition / Concern

A request may be made for a variety of reasons to change the tire size on a vehicle. 

 

Recommendations / Instructions

General Motors will ONLY support a tire calibration for tires that have been sized, tested and designed for the vehicle in question and its applications.  The only way to confirm that a calibration is available would be to visit YOUR sales department.  Using the sales order guide, if you can build a vehicle, using the same make, model year, trim, and meet any restrictions listed in the tire section, GM will have a corresponding calibration available.  

 

Note: When changing tire size for new vehicles prior to the first sale and/or a tire/wheel size that may require a different pressure or alter the cargo carrying capacity of the vehicle, refer to #12-00-89-007B: Dealer Responsibility for Cargo Carrying Capacity Labeling.  

 

Once the tire application has been confirmed per the sales guide, contact Techline Customer Support Center (TCSC) (English: 1-800-828-6860, French: 1-800-503-3222 ) to determine calibration availability. 

Please do not call Technical Assistance Center for these concerns. 

 

Note: There may be a cost to the customer for this service. This is NOT a feature that is covered under the manufacturer's warranty. 

 

 

 

Edited by newdude
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22 minutes ago, TJay74 said:

 

 

No they cant,

 

 

 

ALSO.

 

T1 trucks.  If you have 17s or 18s from the factory, GM has flashes to install the accessory 20s and 22s.  They flash the ECM, BCM, Power Steering and Front Camera Module if it has one.  

 

But I guess GM must be lying there too...

Edited by newdude
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2 hours ago, newdude said:

 

 

 

ALSO.

 

T1 trucks.  If you have 17s or 18s from the factory, GM has flashes to install the accessory 20s and 22s.  They flash the ECM, BCM, Power Steering and Front Camera Module if it has one.  

 

But I guess GM must be lying there too...

 

 

I am guessing this is a new change for the 2019+ trucks then, we all went round and round with this on the K2xx trucks with the GM and the dealers. So my apologies to that and kudos to GM for allowing known tire sizes to be calibrated for in the modules.

The newer lane avoidance, advanced cruise control and collision cameras all add some complexity in allowing the vehicle to drive correctly. We also have a 2019 Audi S4 and it is the same way with Audi, everything has to be correct otherwise some of the systems wont work correctly.

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Mines a '21 10 speed.

 

Was born with 

275/60R20SL's

 

For winter its running on factory take-offs with aftermarket

275/65R18's

 

Truck doesn't seem to care.

All the electronic goodies seem to be working.

 

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10 minutes ago, redwngr said:

Mines a '21 10 speed.

 

Was born with 

275/60R20SL's

 

For winter its running on factory take-offs with aftermarket

275/65R18's

 

Truck doesn't seem to care.

All the electronic goodies seem to be working.

 

I didn't think the truck would do anything different as I have none of the fancy adaptive cruise control or cameras.  I was more worried about incorrect mileage being reported and also the speedometer being off.  Also, if there was an issue I didn't want the dealer/GM to deny warranty due to incorrect mileage on the odometer.

 

FWIW I contacted my local dealership with the TSB number from NewDude's post and they had no issue once I pointed them to it.  At first they adamantly said they couldn't do it, but I provided them PIT3271K and they came around.

 

Rick.

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